1. Field of the Invention
The invention relates to a height adjusting device, a portable computer, and a display, more particularly to a display height adjusting device, and a portable computer and a display respectively having the display height adjusting device.
2. Description of the Related Art
In a conventional notebook computer, a display and a computing device of the notebook computer are interconnected by a hinge. That is, a pivot shaft is provided between the display and the computing device to permit adjustment of an elevational angle of the display by pivotally turning the display relative to the computing device.
However, sometimes there is a height difference between the eye level and the screen of the display, so that the user cannot see the screen comfortably. If the height difference is small, a suitable viewing angle can be achieved by simply adjusting the elevational angle of the display. Where the height difference is large, the user needs to adjust his/her sitting posture or the height of the seat on which he/she is seated, or to raise the notebook computer by placing a book between the notebook computer and the desk surface so as to lower the height difference, which is very inconvenient.
FIG. 1 shows a conventional support device 1 for use in a desk-top display. The support device 1 includes a support member 11, a sliding member 12 extending through the support member 11 and slidable up and down relative to the support member 11, and a constant force spring 13. The support member 11 has a bottom end for mounting on a base 101. The sliding member 12 has a top end for mounting of a display 100. The constant force spring 13 has a top end 131 secured in the support member 11, and a coiled portion 132 at a bottom end which abuts against a bottom end of the sliding member 12. When the sliding member 12 is elevated or lowered relative to the support member 11, the coiled portion 132 of the constant force spring 13 curls upward or is stretched downward. Through the arrangement of the constant force spring 13, the sliding member 12 can be positioned at an arbitrary height. Thus, the position of the display 100 can be adjusted freely through the extension or retraction of the sliding member 12 relative to the support member 11. However, the conventional support device 1 is relatively bulky, and is therefore not suitable for use in notebook computers, which are required to be compact and light.
FIGS. 2 and 3 show a notebook computer display height adjusting device disclosed in R.O.C. Patent No. 251168. An adjusting device 21 as disclosed therein includes a supporting back plate 211 disposed on a rear face of a display 20 of a notebook computer 2, and a spring 212 with a top end connected to a top portion of the supporting back plate 211, and a bottom end connected to a bottom portion of the display 20. Slide groove structures 210 with a guiding function are provided between the rear face of the display 20 and the supporting back plate 211. Thus, the display 20 can be slid upward relative to the supporting back plate 211 by virtue of a resilient restoring action of the spring 212. In addition, the supporting back plate 211 is provided with fasteners 213, and the display 20 has a plurality of fastening holes 214 spaced apart in an up-and-down relationship in the rear face thereof for engaging the fasteners 213. A slide switch 215 is further provided on a front side of the display 20 and is connected to the fasteners 213. When the user needs to adjust the height of the display 20 relative to the notebook computer 2, he/she can manipulate the slide switch 215 to cause the fasteners 213 to disengage laterally from the corresponding fastening holes 214. Through the resilient restoring action of the spring 212, the display 20 can be elevated. Through engagement of the fasteners 213 with the fastening holes 214 at the corresponding height position, the display 20 can be positioned at the desired height.
However, as such a display height adjusting device achieves the function of elevation by means of the slide groove structures 210 between the rear face of the display 20 and the supporting back plate 211, the height to which the display 20 can be elevated is directly limited by the height of the slide groove structures 210. With the current trend of notebook computer products toward smaller and smaller sizes, the height at which the slide groove structures 210 can be disposed is relatively low. Consequently, the height to which the display 20 can be elevated is limited, and is not practically significant.